Tin Can Phones
2 tin cans, 6 to 8 feet of fishing line or string
Take two tin cans (soup cans work well) and poke a small hole in the center of the bottom of each. Cut about 6 to 8 feet of fishing line or string. Poke each end of the string through the hole in each of the cans from the outside and tie several large knots. Pull the string tight, talk into one can and have your friend listen to the other can. As long as you keep the string tight, it really works!